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Black-Stain Root Disease

Scientific Name
Leptographium wageneri
Scientific Author
(W.B. Kendr.) M.J. Wingf.
Taxonomy
Ascomycetes

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Diagnostic Notes
Symptoms

L. wageneri infect the roots and may kill the tree in a few years. Symptoms above the ground resemble those of other root diseases: reduction of growth, thinning of the foliage and leaf chlorosis. A characteristic symptom is a dark brown to black stain in the sapwood of roots, root crown and the lower stem (Smith 1967). Bark beetles often are involved in actually killing disease-weakened trees (Goheen & Cobb Jr 1978).

The fungus:

Conidiophores up to 775 µm long and 4—12 µm wide at the base, up yo 12-septate, mid- to dark brown. Sporogenous apparatus up to 175 µm in length, with mostly 3—5 primary metulae developing in a slightly divergent cluster at the apex of the stipe, measuring 20—50 x 4.5—8 µm. Above the primary metulae are 2-4 further series of metulae, which are usually hyaline and thin-walled. Sympodulae up to 400, 9.4-28 long and 1.7 µm at the base, with scars. Conidia obovoid, elliptical or clavate, truncate at the base, smooth-walled, 2-7.6 x 1.7-3.8 µm, embedded in a translucent brown mucilaginous mass (Kendrick 1962, as Verticicladiella wagenerii).

There are three morphological variants of L. wageneri, which are host-specialized: L. wageneri var. wageneri infects mainly pinyon pine (Pinus monophylla); L. wageneri var. ponderosum infects mainly ponderosa pine (Pinus ponderosa), Jeffrey pine (Pinus jeffreyi), and lodgepole pine (Pinus contorta); L. wageneri var. pseudotsugae infects Douglas-fir (Pseudotsuga menziesii); (Harrigton & Cobb Jr 1984, 1986, 1987, Cobb Jr 1988).

Notes:

1. A detailed description of this species is given by Kendrick (1962).

2. The teleomorph, Ophiostoma wageneri, has been found only on Pinus ponderosa (Cobb Jr 1988) and was described by Goheen & Cobb (1978, as Ceratocystis wagenerii).

3. PCR-based detection methods for this pathogen has been developed (Schweigkofler et al. 2005).

4. Bark beetles can carry the pathogen (Schweigkofler et al. 2005).
More Information
Specimen Contact
Dr Jose R. Liberato
Author
Liberato JR & Hansen EM
Created
09/08/2006 02:07 AEST
Last Updated
28/07/2016 09:11 AEST
Citation
Liberato JR & Hansen EM (2006) Black-Stain Root Disease (Leptographium wageneri ) Updated on 7/28/2016 9:11:06 AM Available online: PaDIL - http://www.padil.gov.au.
Image Use
Free for use under the Creative Commons Attribution 3.0 Australia License

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